We asked Elizabeth Boyle, Ph.D., a professor and meat science specialist at Kansas State University, to give us the rundown on bologna, pastrami and other processed meats. However you slice it, "It's all chemistry," said Boyle.

Here's what to expect when you step up to the deli counter.

Read the labels

Cold cuts consist mainly of trim—that is, the trimmings left over from subprimal cuts of meat—and additives.

Ingredients are listed on the label by weight in descending order. "If the label says 'pork and beef bologna,' pork is the predominant protein," said Boyle.

What's called mechanically separated poultry, the bits of protein mechanically stripped off a carcass, will be labeled as such.

One exception to the labeling rule are spices added solely for flavor in small amounts, less than 2 percent of the formulation, Boyle said. These can simply be called "spices" or "natural flavorings" on the ingredients label.

What about organic?

Organic cold cuts can't contain synthetic preservatives under USDA standards. Boyle said producers will typically use alternative ingredients such as beet or celery powder, which contain naturally occurring nitrates that convert to nitrites and mimic the curing process.

Federal law requires that the label on organic deli meat reads, "No nitrates or nitrites added except for those naturally occurring in [the ingredient]."

Safety at the store

If you get lunch meat sliced to order at the deli counter, take a minute to observe the equipment and the handling of the person behind the counter. Quality control, strictly enforced at the meat processing plant, can slip at the retail level, Boyle said.

"Did they wash their hands? If the slicer is in a cooler, that's awesome. But how often is the slicer cleaned?" she said.

Dates on pre-sliced, packaged lunch meats aren't a be-all, end-all—a "best by" date refers to peak quality, not the point at which spoilage begins—but it's a good idea to choose the latest date out.

A slimy-looking surface on the meat, whether at the deli case or in the package, is not good. "That means there's been some temperature abuse," Boyle said.

Cold storage

Keep lunch meats in the coldest place in your fridge and eat them within three to five days, or else freeze them.

Boyle suggests using airtight freezer bags and layering the meat slices between wax paper, so you can peel them off as needed. They'll keep for a month this way—plenty of time for you to hone the hoagie of your dreams.

An Additive Glossary

With their hard-to-pronounce names, additives can seem scary. They also do a lot for deli meats: enhance meatiness, maintain texture, prevent the growth of dangerous bacteria and extend shelf life. Some of the most common additives in cold cuts include:

Sodium nitrite. A synthetic preservative used in meat-curing that gives lunch meat its pinkish color, helps prevent spoilage and inhibits the growth of the bacteria that can cause botulism and listeria.

While nitrites are crucial to the curing process—and while most nitrites we consume come not from cold cuts but from vegetables and even our own saliva—the USDA limits the amount that can be used in processed meats, Boyle said. Lingering controversy stems from research in the 1970s that found that when subjected to high heat, nitrites form nitrosamines, compounds that in high levels have been linked to cancer.

Monosodium glutamate. A "flavor potentiator," it makes the flavors of deli meats more pronounced, Boyle said. Autolyzed yeast does the same thing.

Hydrolized protein. A texture enhancer made from plant or animal protein. In meat processing speak, it helps with "bind."
Corn syrup, dextrose or other sweeteners. Used as flavoring and in some cases as a browning component.

Phosphates. These help deli meats retain their moisture and texture.

Water. In deli speak, water helps with "machinability," so the meat mixes easily and the salt and seasonings are evenly dispersed, Boyle said. Cold cuts are typically injected with a solution of water, salt, flavorings and phosphate. The percentage of liquid allowed by the USDA varies depending on the product and is listed on the label.